STATE FAIR1945, 100 minutes, CBS/Fox, $19.98.

Belatedly making its first appearance on home video, "State Fair," the only musical Rodgers and Hammerstein wrote directly for the movies, never rises much above the pleasant-trifle level, but trifles this pleasant are scarce, and the film's cute-and-quaint portrayal of Iowa farm life is 100 times preferable to the yucky mush of "Field of Dreams," made 44 years later. Jeanne Crain, timelessly pretty, sings the Oscar-winner "It Might as Well Be Spring" and dreams of losing her virginity at the fair, which won't be hard because even pigs and hogs make hay there. She meets Dana Andrews, a reporter who uses his press pass to get free rides on the roller coaster (!), while brother Dick Haymes, the wooden man with the golden throat, latches onto live wire Vivian Blaine. Comic relief featuring the aforementioned swine is a pain, but the songs hold up, especially "It's a Grand Night for Singing," one of the liltingest waltzes that master lilter Richard Rodgers ever wrote. CBS/Fox's tape transfer does not do justice to the original radiant Technicolor, yet there are still times you may stop and say "wow." Not to be confused with a tacky remake starring Ann-Margret and Pat Boone (or an earlier, nonmusical version with Will Rogers), "State Fair" asks the musical question "Isn't It Kinda Fun?" The answer: Yes, it is. Tom Shales

CRY-BABYPG-13, 1990, 86 minutes, closed-captioned, MCA/Universal Home Video, $91.95.

"Cry-Baby" is basically "Hairspray" without Divine inspiration, a second celebration of '50s cliches from director John Waters, who has found his way into the mainstream. Sort of. Set in Baltimore, this mock-heroic medley of doo-wop, rockabilly, white bucks and bullet bras salutes the social misfits of yesteryear, with lots of fuss and muss but without much conviction. The relentlessly frantic musical features pretty boy Johnny Depp as the teen tough, Cry-Baby Walker, a greaser who falls in love with charm schooler Allison Vernon-Williams, played by lustrous Amy Locane. When Allison throws over her snobby boyfriend (Stephen Mailer), the inevitable rumble between greasers and preppies ensues and though blameless, Cry-Baby is sent to reform school. In the lockup, a bull played by Willem Dafoe attempts to hammer the values of the Eisenhower Age into his delinquent charges, who enthusiastically jailhouse rock the time away. Eventually the young lovers prove the greasers' innocence and the clean-cuts' guilt to avenge the underclass, here a rogues' gallery of inbred geeks. A thin attempt to say something about coming of age, "Cry-Baby" has less to say about learning to be one's own person than 1988's charming "Hairspray." Still, it has its spit-curled charms, its amusing lines and its assortment of funky celebrity cameos -- Patty Hearst, Troy Donahue, Iggy Pop and Polly Bergen among them. Rita Kempley

OPPORTUNITY KNOCKSPG-13, 1990, 103 minutes, closed-captioned, MCA/Universal Home Video, $91.95.

In Donald Petrie's "Opportunity Knocks," Dana Carvey pulls out all the stops to keep us well entertained. He's like the over-eager host at a party, frantically rushing around to make sure everyone's drink is fresh and all the hors d'oeuvre trays are filled. Whatever's necessary, he'll do it -- shtick, dialects, impressions, funny dances, any and everything. And if you're too tired to smile, no problem! He'll pinch up the corners of your mouth for you. The main problem with "Opportunity Knocks," though, is that everything the "Saturday Night Live" cast member does falls into an inoffensive middle range. As a comic, he's perfectly agreeable and, at times, even mildly amusing, but he's been pressed into leading-man service much too soon -- as a star he's undercooked. Playing a con man who offends a local crime boss (James Tolkan) and, as a way of hiding out, assuming the identity of a young financial wizard, he's meant to redeem the film's woefully flimsy central premise. Set in Chicago, where Eddie and his pal Lou (Todd Graff) work nickel-and-dime cons on the street, the film tells the story of a crook reformed by the love of a young doctor (Julia Campbell), who along with her mother and father (Doris Belack and Robert Loggia) believes he is her brother's best friend and takes him under her wing. Essentially, though, the film is a collection of bits, all designed to feature Carvey's various comic skills. But Carvey's talents are palatable only in small helpings. Even his best routines don't seem marked definitively with his stamp. I would love to proclaim that Carvey has what it takes to be a major star. But, no ... not gonna do it. Wouldn't be prudent. At this juncture. Hal Hinson

LOOSE CANNONSR, 1990, 94 minutes, closed-captioned, RCA/Columbia Pictures Home Video, $89.95.

The premise of Bob Clark's "Loose Cannons," a cop comedy starring Dan Aykroyd and Gene Hackman, is close to obscene: A film containing footage of Hitler's final minutes -- including his death at the hands of a young officer named Von Metz, who if he can suppress his Nazi past will almost certainly be elected West German chancellor -- has moved into circulation on the black market. Naturally Von Metz, who is played as an older man by Robert Prosky, would like to see the film destroyed and has even gone to the extreme of attempting to murder everyone who has seen it. It's when all the victims of these grisly murders start appearing around the Washington area that Mac and Ellis (Hackman and Aykroyd) are teamed up to investigate. It's an odd pairing, and not a felicitous one. Mac, whose real passions in life are his shiny vintage woody and his cat, is an old pro with a rowdy streak; Ellis is a full-blown flake who, when faced with violence, begins to slip into alternate identities, taken mostly from old movies and television shows. Watching Aykroyd go through his crazy-man gyrations, you're aware mostly that the film's producers have gotten the wrong comedian for the role. It's Robin Williams, not Aykroyd, who specializes in rapid-fire, channel-switching comedy. For his part, Hackman mostly just stands around watching with the look of a man who has something unspeakable on the sole of his shoe. He shouldn't even be here and he knows it. Others who should have known better are Dom DeLuise, who plays a smut peddler named Gutterman, and Nancy Travis, who plays a foxy member of the Israeli secret service. The rest of the cast and crew seem pretty much to deserve each other. Hal Hinson